If your tyres have steel studs they could be legal according to the law chephy links to, since studded tyres are defined as:
“studded tire” means a tire that has a tread embedded with devices that project beyond the tread and have a hardness of greater than seven on the Mohs scale
Steel, even when hardened, doesn't usually get above 7 on Mohs hardness scale. There are exceptions, of course. My tyres have tungsten carbide studs, so they have a hardness of around 9.